Improve certificate validation registration

Fixed: Certificate validation during startup
Fixed: Errors removing Windows service

Closes #3037
Closes #3038

src/NzbDrone.Core/Security/X509CertificateValidationService.cs

@@ -5,30 +5,22 @@ using System.Security.Cryptography.X509Certificates;
 using NLog;
 using NzbDrone.Common.Extensions;
 using NzbDrone.Core.Configuration;
+using NzbDrone.Core.Lifecycle;
+using NzbDrone.Core.Messaging.Events;
 
 namespace NzbDrone.Core.Security
 {
-    public interface IX509CertificateValidationPolicy
-    {
-        void Register();
-    }
-
-    public class X509CertificateValidationPolicy : IX509CertificateValidationPolicy
+    public class X509CertificateValidationService : IHandle<ApplicationStartedEvent>
     {
         private readonly IConfigService _configService;
         private readonly Logger _logger;
 
-        public X509CertificateValidationPolicy(IConfigService configService, Logger logger)
+        public X509CertificateValidationService(IConfigService configService, Logger logger)
         {
             _configService = configService;
             _logger = logger;
         }
 
-        public void Register()
-        {
-            ServicePointManager.ServerCertificateValidationCallback = ShouldByPassValidationError;
-        }
-
         private bool ShouldByPassValidationError(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
         {
             var request = sender as HttpWebRequest;
@@ -38,11 +30,10 @@ namespace NzbDrone.Core.Security
                 return true;
             }
 
-            var req = sender as HttpWebRequest;
             var cert2 = certificate as X509Certificate2;
-            if (cert2 != null && req != null && cert2.SignatureAlgorithm.FriendlyName == "md5RSA")
+            if (cert2 != null && request != null && cert2.SignatureAlgorithm.FriendlyName == "md5RSA")
             {
-                _logger.Error("https://{0} uses the obsolete md5 hash in it's https certificate, if that is your certificate, please (re)create certificate with better algorithm as soon as possible.", req.RequestUri.Authority);
+                _logger.Error("https://{0} uses the obsolete md5 hash in it's https certificate, if that is your certificate, please (re)create certificate with better algorithm as soon as possible.", request.RequestUri.Authority);
             }
 
             if (sslPolicyErrors == SslPolicyErrors.None)
@@ -50,7 +41,7 @@ namespace NzbDrone.Core.Security
                 return true;
             }
 
-            var host = Dns.GetHostEntry(req.Host);
+            var ipAddresses = GetIPAddresses(request.Host);
             var certificateValidation = _configService.CertificateValidation;
 
             if (certificateValidation == CertificateValidationType.Disabled)
@@ -59,7 +50,7 @@ namespace NzbDrone.Core.Security
             }
 
             if (certificateValidation == CertificateValidationType.DisabledForLocalAddresses &&
-                host.AddressList.All(i => i.IsIPv6LinkLocal || i.IsLocalAddress()))
+                ipAddresses.All(i => i.IsIPv6LinkLocal || i.IsLocalAddress()))
             {
                 return true;
             }
@@ -69,5 +60,20 @@ namespace NzbDrone.Core.Security
 
             return false;
         }
+
+        private IPAddress[] GetIPAddresses(string host)
+        {
+            if (IPAddress.TryParse(host, out var ipAddress))
+            {
+                return new []{ ipAddress };
+            }
+
+            return Dns.GetHostEntry(host).AddressList;
+        }
+
+        public void Handle(ApplicationStartedEvent message)
+        {
+            ServicePointManager.ServerCertificateValidationCallback = ShouldByPassValidationError;
+        }
     }
 }

src/NzbDrone.Host/Bootstrap.cs

@@ -10,7 +10,6 @@ using NzbDrone.Common.Instrumentation;
 using NzbDrone.Common.Processes;
 using NzbDrone.Core.Configuration;
 using NzbDrone.Core.Instrumentation;
-using NzbDrone.Core.Security;
 
 namespace NzbDrone.Host
 {
@@ -40,7 +39,6 @@ namespace NzbDrone.Host
                 var appMode = GetApplicationMode(startupContext);
 
                 Start(appMode, startupContext);
-                _container.Resolve<IX509CertificateValidationPolicy>().Register();
 
                 if (startCallback != null)
                 {